Help! Advice needed on tail structure

[Timmy]

Hello everybody! I've been working on my CL-415 and now that I've got fresh foam I'm looking to build the tail feathers. The V-stab is very big and is a + tail (the H-stab is held by the V-stab) and I don't know how to reinforce it. My current plan is to just use popsicle sticks in between three layers of foam.

I don't have much experience with big tails like this and I've just sorta been going of off the FT Otter tail. Also the H-stab is two layers thick. So my main questions are, is two popsicle sticks on each side enough? Any advice on how to attach the H-stab? Thanks in advance!

Here's a 415 for reference

 

[L Edge]

Built and flown a YC-14 blown flaps transport with H stab on top. I used 2 small dia carbon rods for the elevator that ran all the way across and for the rudder I used 2 carbon rods down the rudder and glued into the fuse. Need to watch out for flutter at high angle of attack if not stiff.

 

[Piotrsko]

Piece of 1/32 basla sandwiched between layers of foam would probably suffice. Like @L Edge said flutter is the main bugaboo but flex is right behind.

 

[dap35]

Hello everybody! I've been working on my CL-415 and now that I've got fresh foam I'm looking to build the tail feathers. The V-stab is very big and is a + tail (the H-stab is held by the V-stab) and I don't know how to reinforce it. My current plan is to just use popsicle sticks in between three layers of foam.
View attachment 228547
View attachment 228548 View attachment 228552
View attachment 228549
I don't have much experience with big tails like this and I've just sorta been going of off the FT Otter tail. Also the H-stab is two layers thick. So my main questions are, is two popsicle sticks on each side enough? Any advice on how to attach the H-stab? Thanks in advance!

Here's a 415 for reference
View attachment 228553

If you can find 1/64" plywood at your local hobby shop you can put a ~1/2" strip on each face of the control surface to keep it from buckling. 1/32 works as well, but is heavier. One of my fellow club members refered to this as a poor man's graphite.

 

[Timmy]

If you can find 1/64" plywood at your local hobby shop you can put a ~1/2" strip on each face of the control surface to keep it from buckling. 1/32 works as well, but is heavier. One of my fellow club members refered to this as a poor man's graphite.

Too late hehe. But I don't think my control surfaces will buckle. I'm not going to go that fast and they seem pretty sturdy.

 

[quorneng]

Rather than popsicle sticks stuck on the side how about two (or more) sticks stuck together at right angles to form a "T" and then inserted into appropriate slots cut into the fin and tail plane.

It would in effect be adding a root wood spar at the joint between the fin and tail plane.

 

[Timmy]

Rather than popsicle sticks stuck on the side how about two (or more) sticks stuck together at right angles to form a "T" and then inserted into appropriate slots cut into the fin and tail plane.
View attachment 228609
It would in effect be adding a root wood spar at the joint between the fin and tail plane.

Thanks but its too late now. Tail already glued and covered. I used wood between the layers of foam plus the popsicle sticks.
Also, is that FreeCAD?

 

[quorneng]

Yes. It seemed the best way to create a 3 view drawing of two popsicle sticks!
I use FreeCad to create printable components for use in planes but not complete airframes.